18 Matching Results

Search Results

Advanced search parameters have been applied.
in subjects: "Strontium 87"  
Results: 1 - 18
open access

Strontium isotopes in carbonate deposits at Crater Flat, Nevada

Description: Strontium isotope studies of carbonates from soils, veins, eolian dust and Paleozoic basement samples near Crater Flat, southwest of Yucca Mountain, provide evidence for the origins of these materials. Vein and soil carbonates have nearly identical ranges of {sup 87}Sr/{sup 86}Sr ratios at the lower end of the pedogenic range. The average {sup 87}Sr/{sup 86}Sr of Paleozoic basement from Black Marble Hill is similar to the {sup 87}Sr/{sup 86}Sr in the eolian dust, perhaps indicating a local sour… more
Date: January 1, 1991
Creator: Marshall, B.D.; Futa, K.; Peterman, Z.E. & Stuckless, J.S.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Preliminary on the isotope hydrology investigations at the Nevada test site: Hydrologic resources management program; FY 1992--1993

Description: A comprehensive isotope data base of the NTS groundwaters collected during FY 92-93 is presented with preliminary interpretations. Multiple samples were collected from over 30 sites on pumped wells and open-holes by wireline bailing. Field water level measurements indicate essentially a bimodal distribution separated by water levels at higher elevations (e.g. Pahute Mesa) from water levels of lower elevations (e.g. Yucca and Frenchman Flats). Down hole temperature measurements have confirmed an… more
Date: January 1994
Creator: Davisson, M. L.; Kenneally, J. M.; Smith, D. K.; Hudson, G. B.; Nimz, G. J. & Rego, J. H.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Preliminary report on isotope abundance measurements in groundwater samples from the Talbert Injection Barrier Area, Orange County Water District

Description: This report discusses isotope abundance measurements made on a collection of groundwater samples from the Orange County Water District. The water samples were collected in May, 1994 as part of a preliminary study conducted by LLNL to assess the feasibility of tracing and dating reclaimed water used in the Talbert Injection Barrier. A set of samples were collected both near to and far from the barrier and also at different depths in available monitoring wells. A variety of elements were selected… more
Date: February 1, 1995
Creator: Hudson, G.B.; Davisson, M.L.; Velsko, C.; Niemeyer, S.; Esser, B. & Beiriger, J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Strontium isotope evolution of pore water and calcite in the Topopah Spring Tuff, Yucca Mountain, Nevada

Description: Pore water in the Topopah Spring Tuff has a narrow range of {delta}{sup 87}Sr values that can be calculated from the {delta}{sup 87}Sr values of the rock considering advection through and reaction with the overlying nonwelded tuffs of the PTn. This model can be extended to estimate the variation of {delta}{sup 87}Sr in the pore water through time; this approximates the variation of {delta}{sup 87}Sr measured in calcite fracture coatings. In samples of calcite where no silica can be dated by oth… more
Date: April 29, 2001
Creator: Marshall, Brian D. & Futa, Kiyoto
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Neutron capture cross sections for /sup 86,87/Sr at Stellar temperatures

Description: Cross sections have been measured from 100 eV to 1 MeV by the neutron-time-of-flight technique. The capture events were recorded by detecting the prompt gamma-ray cascade with two C/sub 6/D/sub 6/ scintillators, and were normalized to standard gold cross sections. The background was determined experimentally by utilizing the ''black resonance'' technique. A /sup 6/Li-glass scintillator was used to monitor the neutron flux. A Maxwellian-averaged capture cross section at kT = 30 keV of 74 +- 3 mb… more
Date: February 1, 1986
Creator: Bauer, R. W.; Mathews, G. J.; Becker, J. A. & Howe, R. E.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Difficulties with inferring neutron cross sections from charged-particle reactions

Description: We have investigated problems associated with inferring cross sections for neutron reactions on unstable nuclei in the mass-90 region from charged-particle reactions on nearby stable targets. We conclude that effects due to precompound evaporation, isospin, and multiple reaction paths severely limit the circumstances under which charged-particle studies may be directly and easily converted to neutron cross sections of useful accuracy. 4 refs., 2 figs.
Date: May 7, 1985
Creator: Gardner, D. G. & Gardner, M. A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Spectroscopy of /sup 87,88,89/Sr with (n,. gamma. ) and (d,p) reactions

Description: Over the recent years the nuclear structure around the N = 50 shell closure, which is very pronounced in the strontium and zirconium isotopes, has been the subject of extensive experimental and theoretical work. On the proton side Z = 38 and Z = 40 provide fairly closed sub-shells. In the strontium isotopes the lg/sub 9/2/ neutron shell is closed at /sup 88/Sr, supplying relatively pure neutron-hole and neutron-particle states with large spectroscopic factors in /sup 87/Sr and /sup 89/Sr, as we… more
Date: January 1, 1988
Creator: Winter, C.; Krusche, B.; Lieb, K.P.; Hlawatsch, G.; Egidy, T.V.; Hoyler, F. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Importance of level structure in nuclear reaction cross-section calculations. Revision 1

Description: It is shown that level-density expressions cannot adequately represent or substitute for level structure information when making calculations of the Hauser-Feshbach type for cross sections or isomer-ratios for nuclei in the first few MeV above their ground state. It is stated that such discrete level information should include both experimentally confirmed and theoretically predicted levels. The utility of discrete level information to optimize level density calculations, to compute isomer rati… more
Date: November 7, 1985
Creator: Gardner, M. A. & Gardner, D. G.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Gamma-ray spectra from neutron capture on /sup 87/Sr

Description: The gamma-ray spectrum following neutron capture on /sup 87/Sr was measured at 3 neutron energies: E/sub n/ = thermal, 2 keV, and 24 keV. Gamma rays were detected in a three-crystal Ge(Li)-NaI-NaI pair spectrometer. Gamma-ray intensities deduced from these spectra by spectral unfolding are presented.
Date: July 1, 1981
Creator: Sullivan, R. E.; Becker, J. A. & Stelts, M. L.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Neutron capture cross sections for /sup 86/Sr and /sup 87/Sr at stellar temperatures. Revision 1

Description: Recent work on s-process nucleosynthesis has focused attention on the investigation of capture cross sections for nuclei in the mass region near the N = 50 closed neutron shell. Of special astrophysical interest are (i) the analysis of the s-process branching through /sup 85/Kr as a monitor of stellar neutron density and temperature and (ii) the investigation of the possible chronometric pair /sup 87/Rb-/sup 87/Sr as an independent measure of the age of the galaxy. For both problems the capture… more
Date: June 25, 1986
Creator: Bauer, R. W.; Mathews, G. J.; Becker, J. A.; Howe, R. E. & Ward, R. A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Report to the DOE Nuclear Data Committee, 1985

Description: Progress is reported on the following measurements: the leakage multiplication from hollow beryllium spheres; /sup 6/Li and /sup 7/Li neutron-induced tritium production cross sections at 15 MeV; fast neutron fission yields; /sup 238/U(t,X) cross sections; neutron capture cross sections for /sup 86/ /sup 87/Sr at stellar temperatures; influence of realistic single particle spacings on precompound decay spectra; spontaneous fissions from a source of /sup 260/Md; and excitation functions from prot… more
Date: February 1, 1985
Creator: White, R.M. & Lanier, R.G.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
Back to Top of Screen